This paper presents the first full thermodynamic description of the hydrogen transfer between acrolein, the simplest a,b-unsaturated aldehyde, and a set of aliphatic alcohols, both primary and secondary. The vapour phase transfer hydrogenation of acrolein into allyl alcohol with various primary and secondary aliphatic alcohols used as hydrogen donors in the presence of MgO as the catalyst has been studied. Despite differentiated reactivity exhibited by these alcohols, a high chemoselectivity ([80%) to allyl alcohol has been observed for all of them. On the basis of thermodynamic calculations it has been found that secondary alcohols as hydrogen donors are more reactive than primary ones. However, ethanol or butan-1-ol have shown the highest reactivity. In their presence yields of allyl alcohol higher than 60% have been noted, which greatly exceed those predicted by thermodynamic calculations based on the following equation: acrolein ? ethanol (butan-1-ol) ? allyl alcohol ? acetaldehyde (butyraldehyde). Although similar yields have been reported in literature, no subsequent nor side reactions have been discussed even though the attained yield cannot be accounted for by this reaction alone. As a possible explanation of the discrepancy the occurrence of a disregarded reaction, for which DG \ 0, has been considered. It has been shown that aldol condensation fulfills these thermodynamic requirements, however, the products of this reaction are noted only at the beginning of the process and the decrease of their amount does not influence the yield of allyl alcohol.

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The reaction of iodine with various metal oxides has been studied in both vapour phase (373–873 K) and in solution in cyclohexane, under anhydrous conditions. The course of the reaction has been revised in accordance with literature and experimental data. Apart from adsorbed iodine molecules ([I2] < 200 μmol·g–1), the presence of I– ions ([I–] < 50 μmol·g–1) has been noted. IOn– ions have been observed only when both water and strong basic sites, such as those on MgO or La2O3, are present. It has been found that the strength of interaction of iodine with metal oxide increases with basicity of the oxide.

The introduction of a halide (Br, I) onto MgO leads to obtaining catalysts whose catalytic activity in transfer hydrogenation of acrolein with ethanol is significantly higher than that of unmodified MgO. In data found in literature, there is no concise view on how the modification of the surface of MgO with a halide affects its surface properties. Although most of the literature studies indicate a dependence of activity on the initial halide‐containing compound and type of halide, no study comprising both these aspects has been performed. The aim of the present study was to conduct measurements of MgO modified with two halides and with two types of initial halide‐containing compounds with surface‐sensitive techniques to determine how each of these factors influences the surface properties of the catalyst. Titration experiments showed that all of the modified catalysts have a smaller diversity of basic site strengths than unmodified MgO. They also revealed that for all studied systems, the modification of the surface leads to the formation of Brønsted acidic sites, which MgO does not possess. XPS spectra indicate that bromine‐modified catalysts give a broader range of surface species than the appropriate iodine‐modified ones. Moreover, they showed that in the case of both iodine‐modified and bromine‐modified catalysts, the one that exhibited the higher concentration of the appropriate halogen on the surface showed a lower activity in catalytic transfer hydrogenation of acrolein with ethanol. Copyright © 2015 John Wiley & Sons, Ltd.

In this laboratory experiment, the synthesis of a supported solid catalyst (Cu/SiO 2 ) and its application in the dehydrogenation of cyclohexanol performed under flow conditions was studied. The experiment was planned for a group of two or three students for two 6 h long sessions. The copper catalyst was synthesized using incipient wetness impregnation of the silica support with copper(II) nitrate trihydrate as the precursor of the active phase. It was then dried, calcined, and reduced. Each step of the synthesis was characterized by color change. The catalytic reaction was performed as a continuous process in a flow reactor, and the postreaction mixture was analyzed using gas chromatography. The laboratory experiment showed practical aspects of heterogeneous catalysis and encouraged students to seek alternative, environmentally friendly methods of organic compound synthesis.

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The reactivity of two series of compounds: alkyl x-oxoalkanoates (x = 2, 3, 4 and 6), and alkyl x-phenyl-y-oxoalkanoates (y = 2 and 4) has been studied in the catalytic transfer hydrogenation (CTH) over magnesium oxide as the catalyst. The catalytic tests have been performed either in liquid or vapor phase with secondary alcohols (2-propanol to 2-octanol) as hydrogen donors. A strong diminution of reactivity of the ketoesters in CTH has been observed, in contrast to simple aliphatic or aralkyl ketones. The occurrence of transalcoholysis between ketoesters and alcohols used as hydrogen donors resulted in the formation of new ketoesters as side products. The hydroxoesters, i.e. the products of the CTH reaction, have been obtained with only moderate to good yields (up to 50 %). It has been found that in the CTH of ketoesters with the carbonyl group in a c position, such as alkyl levulinates and benzoylpropionates, the appropriate lactones (c-valerolactone and 5-phenyl-c-valerolactone) have been formed.